Sen. Kay Hagan (D) of North Carolina (l.) listens as North Carolina Republican Senate candidate Thom Tillis makes a statement during a live televised debate at UNC-TV studios in Research Triangle Park, N.C., Tuesday.

Washington — Four weeks before Election Day, the specter of President Obama is everywhere – Colorado, Georgia, North Carolina, Virginia, West Virginia. In debate after debate Tuesday, Republicans inserted the unpopular president into the conversation early and often, goading Democratic Senate candidates into distancing themselves from Mr. Obama.

In races where an incumbent Democrat is running for reelection, the attacks were the same: You voted with the president 99 (or 96 or 97) percent of the time. And in races for open seats, Democrats were still portrayed as Obama’s best friend.

The answers also came from a cookie-cutter: You are running against me, not President Obama, Democrats replied in lockstep.

In the North Carolina debate, Sen. Kay Hagan (D) was asked for ways in which she disagrees with Obama and the Democrats, and had no trouble answering: On the use of military force in Syria, she said, “I have called on the president to bring that before Congress.”

Senator Hagan, locked in a tight race with state House Speaker Thom Tillis (R), also called on Obama to approve the Keystone XL pipeline, expressed disapproval of trade deals “that send too many jobs overseas,” and said she had “voted against my party’s budget because it had too deep of cuts to the military.”

In Virginia, Sen. Mark Warner (D) also put some distance between himself and Obama, despite the senator’s comfortable lead against GOP challenger Ed Gillespie. Like Hagan, Senator Warner voiced support for the Keystone pipeline. And he backed offshore drilling in Virginia, as long as the state shares in the revenue.

In West Virginia, underdog candidate Natalie Tennant (D) joined her Republican opponent, Rep. Shelley Moore Capito (R) in opposing proposed regulations by the Environmental Protection Agency that would tighten standards on coal-burning power plants.

Political handicappers give Republicans a small advantage in their quest to retake control of the Senate, but nobody rules out Democrats’ chances of hanging on. The good news for both parties Tuesday was that nobody committed any major gaffes (though Tillis misstated one of Hagan's committee assignments in the Senate multiple times before he was corrected). The bad news for Democrats is that Obama’s low job approvals hang like an anchor around their necks – especially in red states.

Obama invited the distancing himself last week when he declared that his policies are “on the ballot” on Nov. 4. But Obama was already firmly on the ballot, in spirit if not literally, well before he made that remark.

The news wasn’t all bad for the president Tuesday. Sen. Mark Udall (D) of Colorado, facing a stiff challenge from Rep. Cory Gardner (R), deflected efforts to get him to criticize the president. And he offered strong support for the Affordable Care Act (ACA), the president’s signature initiative.

"The system was flat-out broken. What we did is put people back in charge of their insurance coverage," Senator Udall said.

In Georgia, Democrat Michelle Nunn hesitated when asked her opinion of the ACA, before she listed ways the law could be improved.

Democrats also came prepared with their own attack lines in Tuesday’s debates, individualized to each state and candidate. In North Carolina, Hagan slammed the state General Assembly under Tillis’s leadership: “He’s sending our teachers to Texas, our film industry to Georgia, and Medicaid dollars to 28 other states. That’s his failed economic policy.”

Ms. Nunn, the former head of a nonprofit, went after Republican opponent David Perdue for his business career, zeroing in on a comment in a 2005 deposition that recently came to light. Mr. Perdue had said he spent “most of his career” in outsourcing – shades of GOP presidential nominee Mitt Romney. On Monday, Perdue said he was proud of the outsourcing he had done, calling it a part of American business.

In Colorado, Udall went after Congressman Gardner for his past support for “personhood” measures both in the state and in federal legislation. Such measures assert that life begins at conception, and would ban some forms of contraception.